It is well known that small children, that is children such as in the age when they may sit by themselves (about 6-7 month) until they master sitting safely in a children's chair (about 2 years), need additional support for sitting properly in the chair. The support helps the child in relieving muscles and the skeleton and hinders the child in bending far out of the chair, possibly safety equipment hindering the child from falling out of children's chairs is used in addition.
In order to obtain maximum support for the child it is known to shape mould the seat of a children's chair and to integrate a cross bow and crotch bar. The disadvantage with shape moulded chair seats is that the seat may not be varied in relation to the size and age of the child. Often, such a seat is combined with a harness in order to secure the child from climbing out of the chair. However, the harness does not provide the extra physical support which may be necessary.
In later years, a development has evolved in the direction of more countries and regions having their own safety measures for equipment to be used by children, such as in children's chairs. This must be taken into account in the development of new children's chairs, but it may be difficult to adapt chairs which have been produced for a long period before such safety provisions were put into force. It is especially difficult to perform such adaptations on chairs that have already been sold for many years, without making physical interventions on the chairs. There are thousands of such chairs around in homes. Further, it is a disadvantage continuously having to change the production of such chairs as changes are made in regulations and to put up production lines adapted to each country and their special regulations. It would therefore also be an environmental advantage to be able to adapt a standard children's chair with adaptive equipment making it simple and reasonable to update the chair without having to throw away the entire chair when changes in regulations happen.
This is for example the case with the children's chair Tripp Trapp® which was developed as early as in 1972 and patented in 1976 and which still is a very popular children's chair in many countries.
The Tripp Trapp® chair is designed to be adjusted in coherence with the body size of the child and therefore has a seat plate and a foot plate which may be moved to different height positions in that they glide in tracks in the side pieces and are locked by tightening the distance between the side pieces. The sitting plate may further be adjusted in the depth position in that a plate is pushed in relation to the backrest which is permanent. The backrest consists of two parallel crosspieces with about constant height and distance in relation to each other. Both crosspieces are arched towards the back in the middle portion to adapt to the users back.
For the Tripp Trapp® chair a children's safety bow was also developed for use with the smallest children as described in Norwegian patent NO 132.782 (Petter Opsvik). The safety bow fits in thereto adapted tracks on the inside of the side pieces, in the same height as the back support device, and is arched forward to define an opening for the child together with the back support device. In installing the safety bow, the safety bow is compressed to slip each of the ends into the tracks in the side pieces and the safety bow thereby locks itself in the correct position by its own tension, without the use of tools of any kind. Possibly, a crotch strap may be used which is threaded onto the safety bow and which is fastened via a hole in the seat plate.
It has also proven difficult to adapt existing chairs and children's equipment to new effective demands, if the above mentioned original functions of the chair are to be maintained at the same time. This is for example the case of the demand for a tall and adapted back on children's chairs to prevent the child in throwing itself backward and hurt the dorsal vertebra or falling out.
From DE 9612828 a combined back support and seat plate padding device is known for use in a children's chair similar to the chair mentioned above. The device has back support with a top part extending above the back rest with a rear sleeve for threading onto the back rest, alternatively a flap for wrapping around the rear side of the back rest and reattaching to the padding device by a zipper. The device being one continuous piece is limited in the adjustment of the seat height as a low position will strain the transition between the seat plate portion and the back support portion. Further, the mounting of the device without zipper would necessitate demounting of the chair, with the help of tools. However, by using a zipper, the device might easily be tampered by a child, thus jeopardizing the functioning of the device.
It is therefore an objective to provide equipment as mentioned above so that the owners of older chairs and new chair may upgrade their chairs according to changes in regulations and standards. Further, that the chair does not need to be equipped as a children's chair for the smallest children when this is not the users situation, namely when the chair is used by a child over the age of 3 or by an adult. It is also an objective to avoid physical adaptations, such as making holes in any of the parts or inserting screws that leave spoiling marks in the chair which will be visible when there no longer is use for the back support device or the safety bow. Such interventions may further result in the risk that the user makes adaptations in the wrong manner, so that the safety is not kept intact. It is therefore an objective with the invention to make the fastening of the additional equipment as intuitive and simple as possible, without the use of tools, and upholding safety at the same time.